[Effect of vitamin D on skin metabolism (author's transl)]

To examine for a possible local action of vitamin D on skin, its histology DNA content, melanogenetic response to UV and proliferative activity (incorporation of 3H thymidine into DNA) were studied on vitamin D deficient and vitamin D fed rats. The skin thickness DNA content and melanogenetic response to UV (assessed as the activity of skin tyrosinase) were greater in vitamin D fed than in vitamin deficient rats. In keratinocyte cell cultures vitamin D (10-9 M-10-12 M) increased DNA synthesis in suprabasal cells whereas it had no effect on DNA synthesis in basal cells. The influence of vitamin D on skin thickness and melanogenetic response to UV could provide an effective feed-back control for protection against UV penetration and vitamin D intoxication.